Pressing Eco brings up the ECO light on the dash and pressing Power brings up the POWER light. But after selecting one of these, pressing the same button again turns off the light. So if both ECO and POWER are off, then what mode is the car in?

Is there a 'normal' mode which is neither Eco or Power? I'm confused.

No light on is de facto Normal Mode. Power mode increases the responsiveness of the throttle and ECO mode decreases the responsivness and reduces the impact of the A/C.

I've not driven a gen 3 Prius yet, I've only sat in one in a showroom. But I recall one of the clips I linked about six months ago, with one of Toyota's product managers in the states explaining all the features, and you had four different driving modes. EV, normal, eco and power. Hope that helps.

EDIT:- It's currently on page 6 of the forum (thread titled 'New Prius new 1-010 prius' started on March 28th. My post is the fourth in that thread, the second clip of the five I linked in that post confirms the info you require, specifically, between 2:36 and 2:54 on that clip). Tch, the lengths I go to!

You can select/deselect the other modes at will, and if no lights are on you will be back in normal D mode.

Personally I hate ECO, use POWER when joining dual carriageways and EV when moving it in/out of the garage without the engine starting.

99% of the time I run in D, with the air-con ON and am very happy with 55 mpg on my relatively short journeys.